A randomized controlled 1-year study of daily deferiprone plus twice weekly desferrioxamine compared with daily deferiprone monotherapy in patients with thalassemia major

BACKGROUND AND OBJECTIVES: The aim of this prospective, randomized, 1-year study was to compare the efficacy and safety of oral deferiprone (DFP) with those of combinations of parenteral desferrioxamine (DFO) with oral DFP. DESIGN AND METHODS: A total of 24 patients with thalassemia major were randomized to receive one of the following two treatments; DFP given at a daily dose of 75 mg/kg in combination with DFO (40-50 mg/kg twice weekly) (n=12) or as single agent (n=12). In addition, 12 patients treated with 40-50 mg/kg DFO 5 days weekly were included as a reference group without randomization. Changes in liver iron concentration (LIC) and serum ferritin (SF) were assessed; total iron excretion (TIE), urinary iron excretion (UIE) and iron balance were calculated. Cardiac function and toxicity were also examined. DESIGN AND METHODS: SF and LIC were significantly reduced after 1 year of combination therapy (p=0.01 and 0.07, respectively). A decrease of LIC was observed in all but one patient (87.5%) following the combination therapy but in only 42% of patients treated with DFP monotherapy. In the DFO reference group, a statistically significant decrease in LIC (p=0.01) associated with a substantial decrease in SF (p=0.08) was observed after 1 year. The combination regimen resulted in greater TIE compared to DFP monotherapy (p=0.08) and was the regimen associated with the highest iron balance compared to DFP monotherapy (p=0.04) or standard DFO treatment (p=0.006). INTERPRETATIONS AND CONCLUSIONS: The addition of subcutaneous DFO twice weekly to oral DFP 75 mg/kg is a highly efficacious and safe chelation therapy providing superior chelation activity to that of DFP and likely has an efficacy profile comparable to that of standard DFO.

Polymorphous oligodendroglioma of Zülch revisited: a genetically heterogeneous group of anaplastic gliomas including tumors of bona fide oligodendroglial differentiation.

A polymorphous variant of oligodendroglioma was described by K.J. Zülch half a century ago, and is only very sporadically referred to in the subsequent literature. In particular, no comprehensive analysis with respect to clinical or genetic features of these tumors is available. From a current perspective, the term polymorphous oligodendroglioma (pO) may appear as contradictory in terms, as nuclear monotony is a histomorphological hallmark of oligodendrogliomas. For the purpose of this study, we defined pO as diffusely infiltrating gliomas felt to be of oligodendroglial rather than astrocytic differentiation and characterized by the presence of multinucleate tumor giant cells and/or nuclear pleomorphism. In a total of nine patients, we identified tumors consistent with this working definition. All tumors were high-grade. We characterized these with respect to clinical, histomorphological and genetic features. Despite clinical and genetic heterogeneity, we identified a subset of tumors of bona fide oligodendroglial differentiation as characterized by combined loss of heterozygosity of chromosome arms 1p and 19q (LOH 1p19q). Those tumors that lacked LOH 1p19q showed a high frequency of IDH1 mutations and loss of alpha thalassemia/mental retardation syndrome X-linked gene (ATRX) immunoreactivity, indicating a possible phenotypic convergence of true oligodendrogliomas and gliomas of the alternative lengthening of telomeres (ALT) pathway. p53 alterations were common irrespective of the 1p19q status. Histomorphologically, the tumors featured interspersed bizarre multinucleate giant tumor cells, while the background population varied from monotonous to significantly pleomorphic. Our findings indicate, that a rare polymorphous - or "giant cell" - variant of oligodendroglioma does indeed exist.

Antisense derivatives of U7 and other small nuclear RNAs as tools to modify pre-mRNA splicing patterns

The importance of alternative splicing for the diversity of the proteome and the large number of genetic diseases that are due to splicing defects call for methods to modulate alternative splicing decisions. Although splicing can be modulated by antisense oligonucleotides, this approach is confronted with problems of efficient delivery and the need for repeated administrations of large amounts of the oligonucleotides. Therefore we have developed methods allowing us to modulate splicing with the help of modified derivatives of the U7 small nuclear RNA involved in histone RNA 3' end processing. Its nuclear accumulation as a stable ribonucleoprotein particle makes U7 snRNA especially useful for this purpose. In particular, U7 derivatives containing two tandem antisense sequences directed against targets upstream and downstream of an exon can induce the efficient and specific skipping of that exon. U7 expression cassettes have been successfully introduced into a great number of cell lines, primary cells or tissues with the help of lentiviral and adeno-associated viral vectors. Examples of these therapeutic strategies in the fields of β-thalassemia, Duchenne muscular dytrophy and HIV/AIDS are discussed.

Stable alteration of pre-mRNA splicing patterns by modified U7 small nuclear RNAs.

In several forms of beta-thalassemia, mutations in the second intron of the beta-globin gene create aberrant 5' splice sites and activate a common cryptic 3' splice site upstream. As a result, the thalassemic beta-globin pre-mRNAs are spliced almost exclusively via the aberrant splice sites leading to a deficiency of correctly spliced beta-globin mRNA and, consequently, beta-globin. We have designed a series of vectors that express modified U7 snRNAs containing sequences antisense to either the aberrant 5' or 3' splice sites in the IVS2-705 thalassemic pre-mRNA. Transient expression of modified U7 snRNAs in a HeLa cell line stably expressing the IVS2-705 beta-globin gene restored up to 65% of correct splicing in a sequence-specific and dose-dependent manner. Cell lines that stably coexpressed IVS2-705 pre-mRNA and appropriately modified U7 snRNA exhibited up to 55% of permanent restoration of correct splicing and expression of full-length beta-globin protein. This novel approach provides a potential alternative to gene replacement therapies.